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The top two carriers warned investors that this quarter will see higher levels of customer churn -- the latest sign that the competitive landscape is shifting in your favor.

Change is afoot, and it's been a long time coming. After T-Mobile (NASDAQ:TMUS)officially kicked off its Un-Carrier campaign in early 2013, the domestic wireless industry was bound to change. CEO John Legere has spearheaded the company's Un-Carrier strategy, launching a number of aggressive pricing plans and other offers. T-Mobile has since followed up with a string of other new promotions and initiatives, tempting potential switchers to take the plunge.

Meanwhile, Sprint (NYSE:S) has been struggling, and the No. 3 carrier is counting on its new leadership to turn the tide. Now, the two top dogs, AT&T (NYSE:T) and Verizon (NYSE:VZ), are starting to feel some competitive pressure as they lose their duopolistic grip on the U.S. wireless industry -- and just this week, both companies tempered investor expectations for the current quarter.

Verizon sticks to the high-endVerizon kicked things off with a news release on Monday that indicated demand for 4G smartphones remains "very strong," and the carrier continues to see momentum in this department. On top of that, Big Red saw 75% of smartphone upgrades qualify as high quality.

Then came the bad news. Verizon is spending heavily on promotional offers, which is helping drive volumes this quarter. These promotional expenses are expected to pressure its wireless segment EBITDA and will put a dent in profitability. At the same time, the No. 1 carrier also acknowledged that retail postpaid disconnects are on the rise due to intense competition and promotions from rivals. Translation: Verizon is spending big on promotions but continues to lose customers.

AT&T is also feeling the burn of churnJust a day later, AT&T CFO John Stephens spoke at an investing conference, similarly indicating that the company expects postpaid churn to increase in the fourth quarter. Though Ma Bell will close out 2014 with "one of [its] best years ever" in terms of full-year postpaid churn, this could be the beginning of a troubling trend.

Stephens explained this is the first year that the new Apple iPhones were launched simultaneously on all four carriers, and because AT&T has the largest install base of iPhone users, it similarly faces higher competition targeting iPhone users. However, this is actually incorrect, as the iPhone 5s launched on all four carriers in 2013.

The CFO also dodged a question about whether or not 2015 will see full-year postpaid churn levels rise compared to 2014 -- competition is only going to continue escalating.

Can you hear me now?None of this is to suggest that AT&T or Verizon are seeing a mass exodus of subscribers that will cripple their respective businesses -- far from it. Rather, small cracks are starting to appear in the armor of the top two players. Both companies continue to have the largest subscriber bases in the U.S. and have been relatively resilient to pricing pressures, in part because of public perceptions around rivals' networks.

That's especially true for T-Mobile, which has long suffered from these negative connotations. But T-Mobile has made impressive progress modernizing its 4G LTE network during the past 12 to 18 months. I personally switched from AT&T to T-Mobile recently and saw my cellular data speeds soar by five times in my area (Denver).

T-Mobile is absolutely catching up in terms of network quality and, over time, it will dispel the perception that its network is inferior -- the primary goal of its current Test Drive offer. Once that is achieved, price will be the determining factor, and T-Mobile has shown its willingness to go straight for the jugular when it comes to pricing.

Sprint's fortunes are a little less clear. The carrier stagnated under Dan Hesse and paid dearly for technological missteps including its original choice of WiMAX over LTE. Meanwhile, the company's heavy debt load -- even after the SoftBank capital infusion -- limits its ability to invest heavily in network infrastructure upgrades that are extremely capital intensive.

To be fair, Verizon also has a massive debt load after buying out Vodafone's stake in Verizon Wireless, but the company's network is already quite mature, so its capital needs are less intense.

You're the real winner of competitionCompetition is only going to pick up in the coming years. T-Mobile has made it quite clear that it has no intention of letting up anytime soon, and it will continue to push against its larger rivals. The Un-Carrier even believes it can overtake Sprint in total customers by year's end.

The net result of all of this is that you, the consumer, will benefit in the form of better promotions, lower prices, and more choices.

Author

Evan is a Senior Technology Specialist at The Motley Fool. He was previously a Senior Trading Specialist at Charles Schwab, and worked briefly at Tesla. Evan graduated from the University of Texas at Austin, and is a CFA charterholder.